accelerated skill gain while jumping rope... children

[mhbuck21]

I just came across this and was wondering if anybody has seen it before... I had a child with fitness hobby jump rope to increase body points. But after the fifth point, I set her to jump again and suddenly she gained 5 points one after the other in a matter of seconds. I received a notice after each point, that she had increased her fitness level and that she had finally maxed the skill. I had never come across this sudden increase. Any ideas abt what happened? I ended saving and keeping the change as nothing else out of the ordinary came up, but was completely taken by surprise...
Mari
edit: Sorry, forgot to add I have all exp. except Pets.

[Engram]

Has the child studied Physiology? This accelerated gain in body skill is normal in sims that have studied Physiology from a book. I sometimes use this for sims who have the LTW to maximise all 7 skills just to get it out of the way quickly so the sim can concentrate on learning the other skills.

[mhbuck21]

Ok, I remember she had a want to study it, but am not sure if she did finish. Would it still work if she just studied a bit? That might explain that jump in speed. I didn´t know it had such a visible effect if you did study those subjects, usually they´re much more subtle.
Thank you, Engram! I´ll be paying more attention to those wants in the future.
Mari